Keysight Technologies 86120B, User Manual

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Measurements Applications
Measuring Laser Drift
Measuring Laser Drift
In this section, you’ll learn how the Keysight 86120B can be used to monitor drift
(changes to a laser’s wavelength and amplitude over time). Drift is measured simul-
taneously for every laser line that is identified at the input. The Keysight 86120B
keeps track of each laser line’s initial, current, minimum, and maximum values and
displays their differences relative to itself. This allows the Keysight 86120B to be
used for laser transmitter evaluation, burn-in, or development. In addition, you can
monitor system performance over time, temperature, or other condition.
The following display shows power and wavelength drift measured on five laser
lines. The
DRIFT
annotation, item ¿, tells you that drift measurements are being
performed. The current relative drift values for wavelength and power are shown in
items ¡ and ¬ respectively. Item Ð indicates the absolute reference values for the
laser line indicated by the cursor
. The reference values are measured before the
measurement starts.
You can restart the drift measurement at any time by pressing the RESET softkey.
All minimum and maximum values are reset to the reference values, and the
Keysight 86120B begins to monitor drift from the current laser line values. Move
the cursor up and down the listing to see the reference wavelength and power of
each laser line.